nodal aspects for me

Node contacts have that fated feeling for me too, as do Moon to Moon aspects, and Juno contacts for some reason. 

Satori has a great post about the composite Vertex on the descendant. 

Sun conjunct Moon can be a wonderful aspect. My sister has her Moon conjunct her husbands Sun, they also have a Venus-Mars conjunction, and Sun-Venus conjunction, they are definitely soulmates and make a great team. 

Sun /Moon conjunctions in synastry are common in long term relationships and marriage, there is a deep connection and often both people feel very comfortable with eachother, of course this does depend on what aspects their sun and moon make (always go back to the natal) so if one of them has moon square saturn then the sun conjunction will highlight that also and bring out that square (fear of emotional closeness perhaps).

I am interested in Vertex too, I saw Satori's post on that, it does seem to be very fated.  This guy who I met over a year ago in a very fated way and am kind of seeing have vertex  (mine) conjunct (his) Sun in synastry and (his) vertex conjunct (my) midheaven, we also have a wide sun conjunct moon synastry. And that always feels very karmic and fated.

Venus/Mars show the sexual attraction, so it would be good to look at that, they also show how you relate socially.  So someone with Venus in Cancer might be a bit shyer than a Venus in Gemini who likes to socialise and meet different people (obviously that is a very brief interpretation and the whole chart would need to be taking into consideration).

Yes and as someone said above Nodes often show fated connections and also the angles.  My last long term relationship my Venus (which is my chart ruler) hit the man's Ascendant and also this guy that I am seeing now my Venus hits his Descendant.  My aunt and uncle who have been married for a long time have Moon on the Ascendant in synastry both ways and they have a big family together (6 kids).